In a cellular wireless communication system, when a signal quality with a serving BS is deteriorated, an MS scans neighbor BSs with reference to a neighbor BS list received from the serving BS. Afterwards, the MS determines handover performance or non-performance using the scanning result, and selects a target BS for handover.
When the MS performs scanning for a Frequency Allocation (FA) different from an operation FA of the serving BS, a communication between the MS and the serving BS is temporarily interrupted during a scanning time duration.
A wireless communication system can provide a femto cell service for solving a service problem of a propagation shadow area while providing a high speed data service. A femto cell means a cell area of a miniature BS, which accesses a mobile communication core network through a broadband network installed within doors such as an office, a house, and such. Here, the miniature BS is a small output BS that a user can install in person. The miniature BS can be called a micro BS, a self configurable BS, a compact BS, an indoor BS, a home BS, a femto BS, and such. In the following description, the miniature BS is named the femto BS.
FIG. 1 illustrates an environment constituted of a macro cell, and FIG. 2 illustrates an environment where a macro cell and a femto cell are mixed.
In the environment of FIG. 2 where a macro BS and a femto BS are mixed, the number of neighbor BSs greatly increases compared to the environment of FIG. 1 constituted of only a macro BS. Thus, in the environment of FIG. 2, an overhead caused by transmission of a neighbor BS list for femto BSs increases.
Alternatively, when a serving BS does not provide the neighbor BS list, an MS has to fully search all FAs. Thus, the MS requires a large amount of operations and, while the MS searches different FAs, communication with the serving BS is interrupted, thus causing a difficulty in providing a real-time service.
Also, in the environment where the macro BS and the femto BS are mixed, in order to detect femto BSs positioned around, an MS has to frequently scan neighbor BSs irrespective of a signal quality with the serving BS. Thus, the MS suffers a frequent interruption of communication with the serving BS, thereby causing deterioration of a real-time service quality and system throughput.